摘要:
In an optical scanning device (10) capable of scanning an information plane of an optical record carrier (5) of different types such as BD, DVD and CD, the diameter of the radiation spot on the detector (7) is dependent on the numerical aperture of the objective system (4) that is used for scanning the record carrier An optimal design of the optical detection system for scanning a BD, result in a small radiation spot for the other types such as DVD and CD. By implementing an optical element (13) that increases the diameter of the radiation spot in the situation a DVD or CD is scanned, the influence of stray light is reduced and the tracking signals are improved
摘要:
An optical scanning device for scanning optical record carriers having cover layers of different thicknesses. The scanning device has a first mode for scanning a first optical record carrier, a second mode for scanning a second optical record carrier and a third mode for scanning third optical record carrier. The device comprises an objective lens system and a switchable optical element having a first discrete state and a different, second discrete state. The element comprises: a fluid system including a first fluid and a different, second fluid (19); a wavefront modifier (17); and a fluid system switch for acting on the fluid system to switch between the first and second discrete states of the element. When the element is in the first discrete state, the wavefront modifier (17) is substantially covered by the first fluid, and when the element is in the second discrete state, the wavefront modifier (17) is substantially covered by the second fluid (19). The wavefront modifier includes a non-periodic phase structure including a plurality of stepped annular zones separated by steps, the zones forming a non-periodic radial pattern, and is characterized in that the wavefront modifier further includes an aspherical surface. The scanning device is arranged to operate using the element in the second state to generate spherical aberration when in the second mode, the aspherical surface of the element in the second state compensating for more than half of the spherical aberration due to the objective lens system and second record carrier in combination.
摘要:
An optical scanning device for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam of a first polarization along a first optical path, and a second radiation beam of a second, different polarization along a second, different optical path. An objective lens system, having an optical axis (19a), is arranged to converge the radiation beams on the information layer A beam-deflecting element (30) comprising a birefringent material is orientated such that each of said polarized radiation beams experiences a different index of refraction upon passing through the birefringent material, and is arranged to refract at least the first radiation beam towards the optical axis.
摘要:
In an optical scanning device (10) capable of scanning an information plane of an optical record carrier (5) of different types such as BD, DVD and CD, the diameter of the radiation spot on the detector (7) is dependent on the numerical aperture of the objective system (4) that is used for scanning the record carrier An optimal design of the optical detection system for scanning a BD, result in a small radiation spot for the other types such as DVD and CD. By implementing an optical element (13) that increases the diameter of the radiation spot in the situation a DVD or CD is scanned, the influence of stray light is reduced and the tracking signals are improved
摘要:
An optical scanning device (1) includes a radiation source (7), a detector (23) and a beam splitter (9). The radiation source (7) provides an incident radiation beam (4, 20) along a first optical path (19a) for scanning an information layer (2) of an optical record carrier (3). The detector (23) detects at least a portion of the radiation beam (22) reflected from the optical record carrier (3). The beam splitter (9) transmits the incident radiation beam (4) received from the radiation source along the first optical path (19a) towards the optical record carrier. The beam splitter (9) also transmits the reflected beam (22) received from the optical record carrier (3) along a second, different optical path (19b) towards the detector. The optical scanning device further includes a beam-deflecting element (30; 130; 230; 330; 630; 830; 930) positioned on the second optical path (19b) between the beam splitter (9) and the detector (23). The beam-deflecting element (30; 130; 230; 330; 630; 830; 930) is arranged to controllably deflect the path of the reflected radiation beam (22) for adjusting the lateral position of said reflected radiation beam incident upon the detector (23) over a predetermined range.
摘要:
A beam-shaping element includes a cavity, a first fluid and a second fluid having different indices of refraction. An optical axis extends through the cavity. The cavity has at least one curved surface extending transverse the optical axis. At least one pump is arranged to pump the fluids between a first configuration in which the first fluid occupies the cavity, and a second configuration in which the second fluid occupies the cavity.
摘要:
A optical scanning device (1) for scanning an information layer (2) with a radiation beam (25) in a writing mode and a reading mode comprises a radiation source (7) for emitting the beam and an objective lens (10) for converging the beam so as to form a scanning spot (19) in the information layer. The device also includes a scanning spot power switch (20) for switching the size of the cross-section of the beam between a first size at the writing mode and a second, larger size at the reading mode so as to switch the rim intensity of the beam between a first intensity level (Irim,writing) at the writing mode and a second, higher intensity level (Irim,reading) at the reading mode, thereby switching the light power of the scanning spot between a first power level (Pwriting) at the writing mode and a second, lower power level (Preading) at the reading mode.
摘要:
A switchable optical element having an optical path (OP) for a radiation beam and having a first state and a second state, the element comprising: a first fluid (12) and a second, different, fluid (14) which are immiscible and which are separated from each other by a fluid meniscus (16); a first, transparent, wall part and a second, transparent, wall part spaced from each other along the optical path; and a fluid switching system which is arranged to apply forces to the first and/or the second fluid in order to switch the element between the first and the second state. The first wall part includes a non-planar wavefront modifier (28), and wherein the fluid switching system is arranged to apply the forces so that when the element is in the first state, the first wall part is covered by the first fluid (12); and when the element is in the second state, the first wall part is covered by the second fluid (14). The switchable optical element is characterised in that the fluid switching system is arranged to switch between the first state and the second state such that when the element is in the first state the second wall part is covered by the second fluid, and when the element is in the second state the second wall part is covered by the first fluid. When the element is in both the first state and the second state, at least part of the fluid meniscus (16) is located on the optical path.
摘要:
An optical scanning device (1) for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam along a first optical path, and a second radiation beam along a second, different optical path. An objective lens system (8) converges the radiation beams on the information layer A beam-deflecting element (30) is arranged to refract said second radiation beam towards the optical axis of the lens system. The beam-deflecting element includes at least one fluid (A). A controller is provided to vary the configuration of the fluid to control the amount of refraction provided by the beam deflector element over a predetermined range.
摘要:
An optical scanning device (1) for scanning at least one information layer (2) of at least one optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam (4) comprising a first wavelength, an objective lens system (8) for converging the first radiation beam on a respective information layer (2), an information detector (23) for detecting at least a portion of the first radiation beam (22) reflected from the respective information layer, for determining information on said layer, and a spherical aberration detection system. The spherical aberration detection system includes an aberration detector (24) for detecting at least a portion of the reflected first radiation beam for determining spherical aberration of the first radiation beam, and a diffractive element (26) for diffracting at least a portion of the reflected first radiation beam towards the aberration detector (24), and for transmitting at least a portion of the reflected first radiation beam towards the information detector (23). In a first mode of operation the grating is arranged to introduce a phase change to an incident portion of a radiation beam for transmitting that portion towards the information detector (23). In a second mode of operation the grating is arranged to introduce a phase change to an incident portion of the reflected first radiation beam for diffracting that portion towards the aberration detector (24).